Semiconductor integrated circuit device

ABSTRACT

A semiconductor integrated circuit device comprises I/O cells arranged around a core region. Each of the I/O cells comprises a level shifter circuit, an I/O logic circuit, and an I/O buffer circuit. An I/O logic region in which the I/O logic circuit is arranged and an I/O buffer region in which the I/O buffer circuit is arranged overlap with a region in which a pad for the I/O cell is arranged. The I/O logic region and the I/O buffer region are arranged side by side in a direction parallel to a side of the core region.

TECHNICAL FIELD Reference to Related Application

This application is based upon and claims the benefit of the priority ofJapanese patent application No. 2011-229075, filed on Oct. 18, 2011, thedisclosure of which is incorporated herein in its entirety by referencethereto. The present invention relates to a semiconductor integratedcircuit device. In particular, it relates to a semiconductor integratedcircuit device in which I/O cells including I/O buffers are arrangedaround a core region.

BACKGROUND

In recent years, as the performance and function of semiconductorintegrated circuit devices improve, the number of inputs/outputs to/froma semiconductor integrated circuit device is increasing. Accordingly,many more I/O cells and bonding pads are being arranged around the coreregion of a semiconductor integrated circuit device. Namely, to decreasethe area of such semiconductor integrated circuit device, it isimportant to decrease the area of a pad region including these I/O cellsand bonding pads.

For example, Patent Literature (PTL) 1 discloses reducing theunnecessary space in an I/O region, to provide a semiconductorintegrated circuit device requiring a smaller area. According to PTL 1,I/O circuit portions and electrostatic discharge (ESD) protectionelement portions included in the I/O region are arranged in the lengthdirection (cross direction) of a side of the core region.

In addition, PTL 2 discloses a technique for improving EMS of an I/Ocircuit portion, without increasing a layout area.

-   [PTL 1]-   Japanese Patent Kokai Publication No. JP2007-096216A (FIG. 2)-   [PTL 2]-   Japanese Patent Kokai Publication No. JP2004-165246A

SUMMARY

The entire disclosures of the above mentioned Patent Literatures areincorporated herein by reference thereto. The following analysis hasbeen made by the present invention.

FIG. 11 schematically illustrates a configuration of the entire chip ofa semiconductor integrated circuit device according to a relatedtechnique. In FIG. 11, the semiconductor integrated circuit deviceincludes: a core region 160 in which CPUs, a RAM, analog regions, andthe like are arranged; and pad regions 170 in which I/O cells and pads(bonding pads) 150 are arranged.

FIG. 14 illustrates a configuration of a pad region 170 in which I/Ocells 140 are arranged. In FIG. 14, a plurality of I/O cells 140 and aplurality of pads 150 are arranged in the pad region 170. Each of thepads 150 is arranged to partially cover some of the I/O cells 140. Eachof the I/O cells 140 includes: a level shifter region 110 in which alevel shifter circuit is arranged; an I/O logic region 120 in which anI/O logic circuit is arranged; and an I/O buffer region 130 in which anI/O buffer circuit is arranged. The I/O buffer region 130 includes:resistor regions 131 and 135 in which resistive elements are arranged;an N buffer region 132 in which an N buffer (NMOS transistor) isarranged; diode element regions 133 and 134 in which diode elements arearranged; and a P buffer region 136 in which a P buffer (PMOStransistor) is arranged. Since each of the pads is used for connectionto a bonding wire or the like, there is a limit to the height and thewidth. Namely, the pad size cannot be decreased with the I/O cell size.However, there is a technique for decreasing the area by efficientlyarranging the pads. Specifically, when many I/O cells and pads arenecessary for a chip size, the pads are arranged in a zigzag pattern asillustrated in FIG. 14.

In contrast, when the number of I/O cells and pads is smaller for a chipsize, the pads can be arranged in a line, instead of in a zigzagpattern. FIG. 12 is a layout diagram illustrating a configuration of asemiconductor integrated circuit device including pads arranged in aline. If the I/O cells 140 illustrated in FIG. 12 are applied to aproduct in which the pads 150 can be arranged in a line, since theheight of each I/O cell 140 is greater than that of each pad 150, it isdifficult to decrease the area of the pad region 170, as illustrated inFIGS. 11 and 12.

In addition, if I/O cells are newly created for in-line pads in whichpads are arranged in a line, ESD protection regions and buffer sizesneed to be redesigned, requiring extra man-hours and manufacturingcosts. In addition, it is difficult to obtain AC/DC characteristicsequivalent to those of the I/O cells 140 for the zigzag pattern pads.

If the size of each I/O cell 140 is simply decreased in the heightdirection of each I/O buffer region 130, the following problems arecaused. FIG. 13 is a layout diagram illustrating a configuration ofpower supply wirings for the I/O cells 140 illustrated in FIG. 12. InFIG. 13, the size of each I/O cell 140 is decreased in the heightdirection of each I/O buffer region 130.

In FIG. 13, a core power supply wiring 141 and a core ground wiring 142supply a core power supply voltage VDD and a core ground voltage VSS toeach level shifter region 110, respectively. In addition, an I/O powersupply wiring 143 and an I/O ground wiring 144 supply an I/O powersupply voltage VCCQ and an I/O ground voltage VSSQ to each I/O logicregion 120, respectively. In addition, an I/O power supply wiring 145and an I/O ground wiring 146 supply the I/O power supply voltage VCCQand the I/O ground voltage VSSQ to each I/O buffer region 130,respectively.

As illustrated in FIG. 13, if the size of each I/O buffer region 130 isdecreased in the height direction (the vertical direction in FIG. 13),the wiring widths of the I/O power supply wirings 143 and 145 and theI/O ground wiring 144 and 146 are accordingly narrowed, resulting in anincrease of wiring resistance. Namely, if the size of each I/O cell 140illustrated in FIG. 12 is simply decreased in the height direction ofeach I/O buffer region 130, since the size of the power supply wiringsarranged thereabove is also decreased, the ESD characteristics and powersupply characteristics could also be deteriorated.

In addition, in the semiconductor integrated circuit device disclosed inPTL 1, the I/O circuit portions and the ESD protection element portionsare arranged in a direction (the cross direction) parallel to a side ofthe core region. In this way, the height in a direction (the verticaldirection) perpendicular to the side can be decreased. However, in thissemiconductor integrated circuit device, wire bonding pads (first pads)and wafer testing pads (second pads) are also arranged in the crossdirection. Thus, in this way, the width of the I/O region in the crossdirection is increased with the widths of these pads in the crossdirection. Namely, based on the semiconductor integrated circuitdisclosed in PTL 1, by decreasing the height of the I/O region, thewidth of the I/O region is increased. Therefore, it is difficult todecrease the area of the I/O region.

Thus, regarding a semiconductor integrated circuit device, there is aneed in the art to decrease the area of each I/O cell by decreasing theheight thereof without increasing the width thereof. Herein, the widthof an I/O cell in a direction parallel to a side of the core region, theside along which the I/O cell is arranged, will be simply referred to as“width,” and the width of the I/O cell in a direction perpendicular tothis side will be referred to as “height.”

According to an aspect of the present disclosure, there is provided asemiconductor integrated circuit device, comprising I/O cells arrangedaround a core region. Each of the I/O cells comprises a level shiftercircuit, an I/O logic circuit, and an I/O buffer circuit. An I/O logicregion in which the I/O logic circuit is arranged and an I/O bufferregion in which the I/O buffer circuit is arranged overlap with a regionin which a pad for the I/O cell is arranged. The I/O logic region andthe I/O buffer region are arranged side by side in a direction parallelto a side of the core region.

The present disclosure provides the following advantage, but notrestricted thereto. Based on the semiconductor integrated circuit deviceaccording to the present disclosure, by arranging the I/O logic regionand the I/O buffer region side by side in the direction parallel to aside of the core region, the height of the I/O cell can be decreased. Inaddition, by arranging both the I/O logic region and the I/O bufferregion to overlap with the region in which the pad for the I/O cell isarranged, an increase in the width of the I/O cell can be prevented. Asa result, the area of the I/O cell can be decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a layout diagram illustrating a configuration of a pad regionin a semiconductor integrated circuit device according to a firstexemplary embodiment.

FIG. 2 schematically illustrates a configuration of the entire chip ofthe semiconductor integrated circuit device according to the firstexemplary embodiment.

FIG. 3 illustrates a plan view and a cross section of an I/O cell of asemiconductor integrated circuit device before measures against alatchup are taken.

FIG. 4 illustrates a problematic point of the semiconductor integratedcircuit device caused before measures against a latchup are taken.

FIG. 5 illustrates a plan view and a cross section of an I/O cell of asemiconductor integrated circuit device according to a second exemplaryembodiment.

FIG. 6 illustrates a meritorious effect obtained by the semiconductorintegrated circuit device according to the second exemplary embodiment.

FIG. 7 is a layout diagram illustrating a configuration of power supplywirings of a semiconductor integrated circuit device according to athird exemplary embodiment.

FIGS. 8A and 8B are block diagrams and layout diagrams illustratingconfigurations of an I/O cell and a power supply cell of thesemiconductor integrated circuit device according to the third exemplaryembodiment.

FIGS. 9A and 9B are layout diagrams illustrating a configuration of asemiconductor integrated circuit device according to a fourth exemplaryembodiment.

FIG. 10 is a layout diagram illustrating a configuration of asemiconductor integrated circuit device according to a fifth exemplaryembodiment.

FIG. 11 schematically illustrates a configuration of the entire chip ofa semiconductor integrated circuit device according to a relatedtechnique.

FIG. 12 is a layout diagram illustrating a configuration of a pad regionof the semiconductor integrated circuit device according to the relatedtechnique.

FIG. 13 is a layout diagram illustrating a configuration of power supplywirings of the semiconductor integrated circuit device according torelated technique.

FIG. 14 is a layout diagram illustrating a configuration of a pad regionof the semiconductor integrated circuit device according to the relatedtechnique.

PREFERRED MODES

First, an outline of the present disclosure will be described. However,the reference symbols in the following outline are merely used asexamples to facilitate understanding of the present disclosure.Therefore, the reference symbols are not intended to limit the presentdisclosure to the illustrated modes.

FIG. 2 is a layout diagram illustrating an overall configuration of asemiconductor integrated circuit device according to the presentdisclosure. FIG. 1 is a layout diagram in which a portion indicated by adashed-dotted line in FIG. 2 is enlarged. In FIGS. 1 and 2, asemiconductor integrated circuit device according to the presentdisclosure comprises I/O cells (40) each including a level shiftercircuit, an I/O logic circuit, and an I/O buffer circuit. The I/O cellsare arranged around a core region (60). An I/O logic region (20) inwhich the I/O logic circuit is arranged and an I/O buffer region (30) inwhich the I/O buffer circuit are arranged overlapping with a region inwhich a pad (50) for the I/O cell (40) is arranged. The I/O logicregion(s) and the I/O buffer region(s) are arranged side by side in adirection parallel to a side of the core region (60).

The I/O buffer region (30) may further include an ESD protection elementregion in which an ESD protection element is arranged. In addition, theI/O logic circuit may include: a circuit for controlling the I/O buffercircuit; an input circuit; a pull up/down circuit; and a control circuittherefore. In each I/O cell (40) in FIG. 1, the I/O logic region (20)and the I/O buffer region (30) are arranged in the same way. However,the I/O logic region (20) and the I/O buffer region (30) may be arrangeddifferently (left-right reversal in FIG. 1) in an I/O cell (40).

By arranging the I/O logic region(s) (20) and the I/O buffer region(s)(30) side by side in a direction parallel to a side of the core region(60), the height of the I/O cell(s) (40) can be decreased. In addition,by arranging both the I/O logic region (20) and the I/O buffer region(30) to overlap with a region in which the pad (50) for the I/O cell(40) is arranged, an increase in the width of the I/O cell can beprevented. Thus, based on the semiconductor integrated circuit device,by decreasing the area of the I/O cell (40), the area of the pad region(70) can be decreased. Namely, the semiconductor integrated circuitdevice can be formed to have a smaller area than the semiconductorintegrated circuit device (FIGS. 11 and 12) according to the relatedtechnique.

As illustrated in FIG. 5, it is preferable that a deep N-well DNWincluded in the I/O logic region (20) and a deep N-well DNW included inthe I/O buffer region (30) be separated from each other. By separatingthe I/O buffer region (30) and the I/O logic region (20) with use of adeep NWEL structure (DNW), a latchup can be prevented.

As illustrated in FIG. 7, it is preferable that the I/O logic circuitand the I/O buffer circuit share a first wiring (I/O power supply wiring43) supplying a first voltage (I/O power supply voltage VCCQ) and asecond wiring (I/O ground wiring 44) supplying a second voltage (I/Oground voltage VSSQ). In this way, the power-supply peripheral wiringsconnected to the I/O cell (40) can have a wider width than those of thesemiconductor integrated circuit (FIG. 13) according to the relatedtechnique. Thus, power can be supplied more stably.

As illustrated in FIG. 7 and FIG. 8A, it is preferable that the I/Obuffer circuit (37) include a P buffer (PMOS transistor P1) and an Nbuffer (NMOS transistor N1) and that a P buffer region (36) in which theP buffer (P1) is arranged be arranged beside a level shifter region (10)in which the level shifter circuit (11) is arranged. In this way, acommon I/O power supply voltage (VCCQ) can easily be supplied to thelevel shifter circuit (11) and the P buffer (P1).

As illustrated in FIG. 8A, the I/O buffer region (30) may include a PMOStransistor (P1), an NMOS transistor (N1), first and second resistiveelements (R2 and R1), and first and second diode elements (D2 and D1).The PMOS transistor (P1) may include a gate terminal connected to the IOlogic circuit (21), one of a source terminal and a drain terminalconnected to a back-gate terminal and the first wiring (I/O power supplywiring 43), and the other one of the terminals connected to a firstterminal of the first resistive element (R2). The first resistiveelement (R2) may include a second terminal connected to the pad (PAD),and the first diode element (D2) may be connected between the firstwiring (43) and the pad (PAD). The NMOS transistor (N1) may include agate terminal connected to the IO logic circuit (21), one of a sourceterminal and a drain terminal is connected to a back-gate terminal andthe second wiring (I/O ground wiring 44), and the other one of theterminals is connected to a first terminal of the second resistiveelement (R1). The second resistive element (R1) may include a secondterminal connected to the pad (PAD), and the second diode element (D1)may be connected between the second wiring (44) and the pad (PAD).

As illustrated in FIG. 8A, FIGS. 9A and 9B, it is preferable that thelevel shifter region (10) in which the level shifter circuit (11) isarranged include: a first voltage region (I/O voltage region 12) inwhich a circuit supplying a first power supply voltage (I/O power supplyvoltage VCCQ) to the I/O logic circuit (21) is arranged; and a secondvoltage region (core voltage region 13) in which a circuit supplying asecond power supply voltage (core power supply voltage VDD) to the corelogic circuit (61) is arranged. In addition, it is preferable that thefirst voltage region (12) be arranged within the I/O logic region (20)and that the second voltage region (13) be arranged between the coreregion (60) and a pair of the I/O logic region (20) and the I/O bufferregion (30). With this configuration, the height of the I/O cell (40)can be decreased further.

(First Exemplary Embodiment)

A semiconductor integrated circuit device according to a first exemplaryembodiment will be described with reference to the drawings. FIG. 1 isan enlarged view of a configuration of a pad region in a semiconductorintegrated circuit device according to the present exemplary embodiment.In FIG. 1, a plurality of I/O cells 40 are arranged in a pad region 70.In addition, each of the I/O cells 40 includes: a level shifterregion(s) 10 in which a level shifter circuit is arranged; an I/O logicregion(s) 20 in which an I/O logic circuit is arranged; and an I/Obuffer region(s) 30 in which an I/O buffer circuit is arranged.

The level shifter region(s) 10 is arranged along a side of a core region60. The I/O logic region(s) 20 and the I/O buffer region(s) 30 arearranged side by side in a direction (the cross direction in FIG. 1)parallel to the side of the core region 60. In addition, both the I/Ologic region 20 and the I/O buffer region 30 overlap with a region inwhich a pad (bonding pad) 50 for the corresponding I/O cell 40 isarranged.

By arranging the I/O logic region 20 and the I/O buffer region 30 sideby side in the direction parallel to the side of the core region, theI/O cell 40 can have a height less than any one of the I/O cells 140 inwhich the I/O logic region 120 and the I/O buffer region 130 arearranged in the vertical direction as illustrated in FIG. 12. Inaddition, by arranging both the I/O logic region 20 and the I/O bufferregion 30 to overlap with the region in which the pad 50 for thecorresponding I/O cell 40 is arranged, an increase in the width of theI/O cell (in the cross direction in FIG. 1) can be prevented. Thus,based on the semiconductor integrated circuit device according to thepresent exemplary embodiment, since the area of each I/O cell 40 isdecreased, the pad region 70 requires a smaller area than the pad region170 according to the related technique.

FIG. 2 schematically illustrates a configuration of the entire chip ofthe semiconductor integrated circuit device according to the presentexemplary embodiment. As an example, an overall view of thesemiconductor chip is illustrated in FIG. 2 in which the I/O cells 40according to the present exemplary embodiment are used and the pads 50are arranged in a line. In FIG. 2, the semiconductor integrated circuitdevice includes: the core region 60; and the pad regions 70 arrangedaround the core region 60. In each of the pad regions 70, a plurality ofI/O cells 40 and pads 50 for the respective I/O cells 40 are arranged.

Based on the semiconductor integrated circuit device according to thepresent exemplary embodiment, each pad region 70 can be formed to have asmaller area than the pad region 170 (FIG. 12) in the semiconductorintegrated circuit device according to the related technique. As aresult, the device can have a smaller size than the semiconductorintegrated circuit device (FIG. 11) according to the related technique.The inventors confirmed that the size of each I/O cell 40 (FIG. 1)according to the present exemplary embodiment can be decreased in theheight direction by 56 um compared with any one of the I/O cells 140(FIG. 12) according to the related technique and that the chip size canbe decreased by 112 um (56 um (one side)×2=112 um).

Each of the I/O buffer regions 30 may include ESD protection resistors(resistive elements R1 and R2 and diode elements D1 and D2) and outputbuffers (NMOS buffer N1 and PMOS buffer P1), as illustrated in FIGS. 8Aand 8B. By forming these components identical to those arranged in eachof the buffer regions in the zigzag-pattern-pad I/O cells according tothe related technique, ESD resistance properties and AC/DCcharacteristics of the buffer identical to those of the I/O bufferaccording to the related technique can be achieved.

According to the related technique, each I/O logic region 120 isarranged on (in the vertical direction in FIG. 12) an I/O buffer region130 in the semiconductor integrated circuit device (FIGS. 11 and 12).However, according to the present exemplary embodiment, each I/O logicregion 20 is arranged beside an I/O buffer region 30. Consequently, theheight (in the vertical direction in FIG. 1) of each I/O cell 40 can bedecreased. In addition, the pads 50 are arranged at minimum intervals of65 um, and the width (in the cross direction in FIG. 1) of each I/O cell40 is set to be less than the minimum intervals.

In the present exemplary embodiment, each I/O cell 40 can be formed tohave a lower height by arranging the I/O logic region 20 and the I/Obuffer region 30 side by side in a direction parallel to a side of thecore region 60. In addition, by arranging both the I/O logic region 20and the I/O buffer region 30 to overlap with the region in which the pad50 for the corresponding I/O cell 40 is arranged, an increase in thewidth of the I/O cell 40 is prevented. As a result, each I/O cell 40 canhave a significantly smaller area than any one of the I/O cells 140according to the related technique.

(Second Exemplary Embodiment)

A semiconductor integrated circuit device according to a secondexemplary embodiment will be described with reference to the drawings.If each I/O logic region 20 is arranged beside an I/O buffer region 30as in the first exemplary embodiment, a latchup is caused easily. In thepresent exemplary embodiment, a semiconductor integrated circuit deviceincluding a configuration for preventing a latchup is provided.

First, a mechanism of causing a latchup will be described with referenceto FIGS. 3 and 4. FIG. 3 illustrates a plan view of an I/O cell 40 of asemiconductor integrated circuit device and a cross section taken alongline A-A′. In FIG. 3, the semiconductor integrated circuit device has adeep N-well (DNL) structure, and the I/O buffer region 30 and the I/Ologic region 20 are not separated.

As illustrated in FIG. 3, a P-NW-PW-N parasitic thyristor element isformed in a P region P immediately under a pad PAD, an N-type well NWextending in the I/O buffer region 30 and I/O logic region 20, a P-typewell PW in the I/O logic region 20, and an N region N immediately underan I/O ground.

FIG. 4 is an equivalent circuit corresponding to the cross section inFIG. 3. If a surge current flows from the pad PAD, a base current from atransistor T1 flows in the direction of a current I1. If the current I1flows, a transistor T2 is brought in an on-state. As a result, a currentI2 flows. If such phenomenon is caused, unless the power supply isturned off, the current endlessly continues to flow, which leads todestruction of an element.

Namely, if the configuration illustrated in FIG. 3 is used, since athyristor structure is formed by parasitic transistors, a surge currentfrom the pad PAD causes a latchup and an overcurrent. As a result, anelement could be destroyed.

FIG. 5 illustrates a configuration illustrating a semiconductorintegrated circuit device according to the present exemplary embodiment.FIG. 5 is a plan view of an I/O cell 40 of the semiconductor integratedcircuit device and a cross section taken along line A-A′. In FIG. 5, thesemiconductor integrated circuit device has a deep N-well (DNL)structure, and the I/O buffer region 30 and the I/O logic region 20 areseparated.

In FIG. 5, a deep N well structure is used, and the I/O buffer region 30and the I/O logic region 20 are divided. Namely, an N well NW and thedeep N well DNW in the I/O logic region 20 are separated from the N wellNW and the deep N well DNW in the I/O buffer region 30 by a P-typesubstrate P-Sub.

FIG. 6 is an equivalent circuit corresponding to the cross section inFIG. 5. As is clear from FIGS. 5 and 6, based on the semiconductorintegrated circuit device according to the present exemplary embodiment,a thyristor structure is not formed by parasitic transistors asillustrated in FIG. 3.

Thus, as illustrated in FIG. 5, by using the deep N wells DNWs andachieving element separation, a latchup caused by a surge current fromthe pad PAD can be prevented. In addition, with this configuration, thedistance between the buffer circuit and the logic circuit can beshorted, and an increase in the width of each I/O cell 40 (in the crossdirection in FIG. 1) can be prevented. In addition, with theconfiguration illustrated in FIG. 5, even if a current flows through theI/O buffer region 30 and a noise is caused, since the I/O logic region20 also has a DNW structure, a malfunction by noise propagation israrely caused, counted as a meritorious effect.

(Third Exemplary Embodiment)

A semiconductor integrated circuit device according to a third exemplaryembodiment will be described with reference to the drawings. Asdescribed above with reference to FIG. 13, if the size of each I/O cell140 of the semiconductor integrated circuit (FIGS. 11 and 12) accordingto the related technique is decreased in the height direction (thevertical direction in FIG. 13), the widths of the I/O power supplywirings 143 and 145 and the I/O ground wirings 144 and 146 aredecreased. As a result, the power supply characteristics aredeteriorated. In the present exemplary embodiment, a semiconductorintegrated circuit device that does not have such problem is provided.

FIG. 7 is a layout diagram illustrating a configuration of power supplywirings of a semiconductor integrated circuit device according to thepresent exemplary embodiment. FIG. 7 illustrates power-supply peripheralwirings formed in a wiring layer above the I/O cells 40.

In FIG. 7, the I/O logic circuit arranged in each I/O logic region 20and the I/O buffer circuit arranged in each I/O buffer region 30 sharean I/O power supply wiring 43 supplying an I/O power supply voltage VCCQand an I/O ground wiring 44 supplying an I/O ground voltage VSSQ.Namely, based on the semiconductor integrated circuit device accordingto the present exemplary embodiment, the I/O power supply wiring 43 andthe I/O ground wiring 44 are shared by each I/O buffer region 30 andeach I/O logic region 20.

If the size of each I/O cell 140 is decreased in the height direction asin the semiconductor integrated circuit device according to the relatedtechnique, the widths of all the I/O power supply wirings 143 and 145and the I/O ground wirings 144 and 146 are decreased. In contrast,according to the present exemplary embodiment, the power-supplyperipheral wirings, that is, the I/O power supply wiring 43 and the I/Oground wiring 44 connected to the I/O cells 40, can be formed to have awider width than those of the semiconductor integrated circuit accordingto the related technique. Thus, power can be supplied more stably, andthe ESD resistance properties can be improved.

FIGS. 8A and 8B illustrate block diagrams and layout diagramsillustrating configurations of an I/O cell 40 and a power supply cell 80of the semiconductor integrated circuit device according to the presentexemplary embodiment. FIG. 8A is a block diagram and a layout diagramillustrating a configuration of an I/O cell 40. FIG. 8A illustrates anI/O cell 40 and a core logic circuit 61 arranged in the core region 60(FIG. 2). In FIG. 8A, the I/O cell 40 includes a level shifter circuit11, an I/O logic circuit 21, and an I/O buffer circuit 37. The levelshifter circuit 11, the I/O logic circuit 21, and the I/O buffer circuit37 are arranged in a level shifter region 10, an I/O logic region 20,and an I/O buffer region 30 in FIG. 7, respectively.

The I/O buffer circuit 37 includes a P buffer (PMOS transistor) P1, an Nbuffer (NMOS transistor) N1, resistive elements R1 and R2, and diodeelements D1 and D2. The P buffer P1, the resistive element R2, the diodeelement D2, the diode element D1, the N buffer N1, and the resistiveelement R1 are arranged in a P buffer region 36, a resistor region 35, adiode element region 34, a diode element region 33, an N buffer region32, and an resistor region 31 in FIG. 7, respectively.

The core logic circuit 61 is connected to the level shifter circuit 11of the I/O cell 40 and is supplied with a core power supply voltage VDDand a core ground voltage VSS. The level shifter circuit 11 is connectedto the core logic circuit 61 and the I/O logic circuit 21 and issupplied with the core power supply voltage VDD, the I/O power supplyvoltage VCCQ, and the core ground voltage VSS. The I/O logic circuit 21is connected to the level shifter circuit 11 and gate nodes of the Pbuffer P1 and the N buffer N1 and is supplied with the I/O power supplyvoltage VCCQ and the I/O ground voltage VSSQ. The P buffer P1 isconnected between the I/O power supply wiring 43 and the resistiveelement R2. The resistive element R2 is connected between the P bufferP1 and the pad PAD. The diode element D2 is connected between the I/Opower supply wiring 43 and the pad PAD. The N buffer N1 is connectedbetween the I/O ground wiring 44 and the resistive element R1. Theresistive element R1 is connected between the N buffer N1 and the padPAD. The diode element D1 is connected between the I/O ground wiring 44and the pad PAD.

In FIGS. 7 and 8A, the P buffer region 36 in which the P buffer P1 isarranged is arranged beside the level shifter region 10 in which thelevel shifter circuit 11 is arranged. In this way, a common I/O powersupply voltage VCCQ can easily be supplied to the level shifter circuit11 and the P buffer P1.

FIG. 8B illustrates a circuit diagram and a layout diagram of the powersupply cell 80. FIG. 8B illustrates a configuration of an I/O powersupply cell, as an exemplary power supply cell. In FIG. 8B, the powersupply cell 80 includes circuits A and B. The circuit A includes acapacitive element C1, resistive elements R3 to R6, and inverters IN1and IN2. The circuit B includes a resistive element R7, a MOS transistorM1, and a diode element D3.

Regarding this power supply cell 80, too, as the lower diagram in FIG.8B illustrates, by arranging a circuit A region 81 in which the circuitA is arranged and a circuit B region 82 in which the circuit B isarranged side by side in a direction (the cross direction in FIG. 1)parallel to a side of the core region 60, as in the I/O cell 40illustrated in FIG. 8A, the size in the vertical direction (the verticaldirection in FIG. 8B) can be decreased.

(Fourth Exemplary Embodiment)

A semiconductor integrated circuit device according to a fourthexemplary embodiment will be described with reference to the drawings.The present exemplary embodiment provides a variation of the I/O cells40 of the semiconductor integrated circuit device according to the firstexemplary embodiment. FIGS. 9A and 9B are layout diagrams illustrating aconfiguration illustrating a semiconductor integrated circuit deviceaccording to the present exemplary embodiment.

In the first exemplary embodiment, as illustrated in FIG. 1, each levelshifter region 10 in which a level shifter circuit is arranged and eachI/O logic region 20 in which an I/O logic circuit is arranged areseparated. In the present exemplary embodiment, by moving part of eachlevel shifter circuit to the corresponding I/O logic region, the height(in the vertical direction in FIGS. 9A and 9B) of each I/O cell 40 canbe further decreased.

In FIGS. 8A and 9, the level shifter region 10 in which the levelshifter circuit 11 is arranged includes: an I/O voltage region 12 inwhich a circuit supplying the I/O power supply voltage VCCQ to the I/Ologic circuit 21 is arranged; and a core voltage region 13 in which acircuit supplying the core power supply voltage VDD to the core logiccircuit 61 is arranged. In the present exemplary embodiment, the I/Ovoltage region 12 is arranged within the I/O logic region 20, and thecore voltage region 13 is arranged between the core region 60 (notillustrated in FIGS. 9A and 9B) and a pair of the I/O logic region 20and the I/O buffer region 30.

With this configuration (FIG. 9B) according to the present exemplaryembodiment, the height of each I/O cell 40 can be decreased further thanthe I/O cell 40 (FIG. 9A) in which all the circuits forming the levelshifter circuit 11 are arranged in the level shifter region 10.

(Fifth Exemplary Embodiment)

A semiconductor integrated circuit device according to a fifth exemplaryembodiment will be described with reference to the drawings. The presentexemplary embodiment provides a variation of the power supply cell (FIG.8B). FIG. 10 is a layout diagram illustrating a configuration of asemiconductor integrated circuit device according to the presentexemplary embodiment.

A power supply cell is created by dividing the circuit B of the powersupply cell 80 illustrated in FIG. 8B into two columns and arranging thecircuit A of the power supply cell 80 in a gap between cells. In thisway, ESD resistance properties can be improved, without increasing thearea in the cross direction (the cross direction in FIG. 10). Inaddition, as illustrated in FIG. 10, by arranging an inter-power-supplycapacity cell in a gap available between cells, power supplystabilization can be achieved.

The disclosure of the above Patent Literatures is incorporated herein byreference thereto. Modifications and adjustments of the exemplaryembodiment are possible within the scope of the overall disclosure(including the claims) of the present invention and based on the basictechnical concept of the present invention. Various combinations andselections of various disclosed elements (including each element of eachclaim, each element of each exemplary embodiment, each element of eachdrawing, etc.) are possible within the scope of the claims of thepresent invention. That is, the present invention of course includesvarious variations and modifications that could be made by those skilledin the art according to the overall disclosure including the claims andthe technical concept. Particularly, any numerical range disclosedherein should be interpreted that any intermediate values or subrangesfalling within the disclosed range are also concretely disclosed evenwithout specific recital thereof.

REFERENCE SIGNS LIST

-   10, 110 level shifter region-   11 level shifter circuit-   12 I/O voltage region-   13 core voltage region-   20, 120 I/O logic region-   21 I/O logic circuit-   30, 130 I/O buffer region-   31, 35, 131, 135 resistor region-   32, 132 N buffer region-   33, 34, 133, 134 diode element region-   36, 136 P buffer region-   37 I/O buffer circuit-   40, 140 I/O cell-   41, 141 core power supply wiring-   42, 142 core ground wiring-   43, 143, 145 I/O power supply wiring-   44, 144, 146 I/O ground wiring-   50, 150 pad-   60, 160 core region-   61 core logic circuit-   70, 170 pad region-   80 power supply cell-   81 circuit A region-   82 circuit B region-   A, B circuit-   C1 capacitive element-   D1-D3 diode element-   DNW deep N-well-   IN1, IN2 inverter-   M1 MOS transistor-   N1 N buffer (NMOS transistor)-   NW N-type well-   P1 P buffer (PMOS transistor)-   PAD pad-   P-Sub P-type substrate-   PW P-type well-   R1-R7 resistive element-   T1-T5 transistor-   VCCQ I/O power supply voltage-   VDD core power supply voltage-   VSS core ground voltage-   VSSQ I/O ground voltage

What is claimed is:
 1. A semiconductor integrated circuit device,comprising: a core region in which core logic circuit is arranged; and aplurality of I/O cells arranged in a first direction, each of theplurality of I/O cells comprising a bonding pad, an I/O logic circuit,and an I/O buffer circuit, wherein an I/O logic region in which the I/Ologic circuit is arranged and an I/O buffer region in which the I/Obuffer circuit is arranged are disposed under the bonding pad in planview, and wherein the I/O logic region and the I/O buffer region arearranged side by side in the first direction.
 2. The semiconductorintegrated circuit device according to claim 1, wherein a deep N-wellincluded in the I/O logic region and a deep N-well included in the I/Obuffer region are separated from each other.
 3. The semiconductorintegrated circuit device according to claim 1, wherein the I/O logiccircuit and the I/O buffer circuit share a first wiring supplying afirst voltage and a second wiring supplying a second voltage.
 4. Thesemiconductor integrated circuit device according to claim 2, whereinthe I/O logic circuit and the I/O buffer circuit share a first wiringsupplying a first voltage and a second wiring supplying a secondvoltage.
 5. The semiconductor integrated circuit device according toclaim 3, wherein the first voltage and the second voltage are a powersupply voltage and a ground voltage, respectively, for the I/O buffercircuit and the I/O logic circuit.
 6. The semiconductor integratedcircuit device according to claim 3, wherein each of the plurality ofI/O buffer circuit includes a level shifter circuit, a P buffer and an Nbuffer, and wherein a P buffer region in which the P buffer is arrangedis arranged beside a level shifter region in which the level shiftercircuit is arranged.
 7. The semiconductor integrated circuit deviceaccording to claim 3, wherein the I/O buffer region comprises a PMOStransistor, an NMOS transistor, first and second resistive elements, andfirst and second diode elements, the PMOS transistor has a gate terminalconnected to the IO logic circuit, one of a source terminal and a drainterminal connected to a back-gate terminal and the first wiring, and theother one of the terminals connected to a first terminal of the firstresistive element, the first resistive element has a second terminalconnected to the pad, the first diode element is connected between thefirst wiring and the pad, the NMOS transistor has a gate terminalconnected to the IO logic circuit, one of a source terminal and a drainterminal is connected to a back-gate terminal and the second wiring, andthe other one of the terminals is connected to a first terminal of thesecond resistive element, the second resistive element has a secondterminal connected to the pad, and the second diode element is connectedbetween the second wiring and the pad.
 8. The semiconductor integratedcircuit device according to claim 1, wherein each of the plurality ofI/O cells includes a level shifter circuit; wherein the level shifterregion in which the level shifter circuit is arranged includes: a firstvoltage region in which a circuit supplying a first power supply voltageto the I/O logic circuit is arranged; and a second voltage region inwhich a circuit supplying a second power supply voltage to the corelogic circuit is arranged, and wherein the first voltage region isarranged within the I/O logic region, and the second voltage region isarranged between the core region and a pair of the I/O logic region andthe I/O buffer region.